A number of recent studies have explored how and when presidents use signing statements to shape the interpretation and implementation of statutes (e.g., Bradley and Posner 2006; Cooper 2005; Kelley 2007a; Kelley and Marshall 2008; Pfiffner 2007). Some emphasize the historical bases for the practice of attaching commentary to bills in the form of a signing statement (Cooper 2005; Kelley 2007a), while others work across administrations to describe presidential practices (Bradley and Posner 2006). Only recently have scholars sought to statistically estimate the impact of factors that drive those statements on the likelihood that a president signs a statement to accompany legislation that he signs. For instance, Kelley and Marshall (2008) show that presidents are more likely to sign statements when there is gridlock and also in the case of major legislation; Kelley and Marshall (n.d.) describe how presidents link veto threats and the use of the signing statement. Those papers, though, consider both types of signing statements: rhetorical (when the president lauds the Congress and others for their work on the legislation) and constitutional (when the president offers his view about how the legislation should be interpreted and implemented).
Political scientists often focus on the signing statement as part of the president's toolkit for shaping policy implementation. Likewise, the legal conversation about signing statements has come to emphasize their role in the president's arsenal of tools for bending policy closer to his own preferences. Walter Dellinger, then assistant attorney general, argued in a 1993 memorandum to Bernard N. Nussbaum (counsel to the president), that one "generally uncontroversial" purpose of signing statements was "to guide and direct Executive officials in interpreting or administering a statute." (1) For Magill, signing statements can be an effective "ex ante" method of presidential control since "The President could offer a wide variety of views in such statements, including his view of the substantive meaning of ambiguous statutory provisions, his view of how the statute should be implemented and enforced, or as Presidents in fact have frequently done, his view that certain provisions are or may be unconstitutional" (2007, 31). In her view, one of the most effective ways to use signing statements has been to "identify the priorities that should animate enforcement of the statute and those that should not" (2007, 50).
Yet, since the 1980s legal scholars have also debated the legitimacy of the president's use of statements to express his views about the meaning of statutes (e.g., Bradley and Posner 2006; Cross 1988; Garber and Wimmer 1987). For instance, Garber and Wimmer (1987) argue that courts should not refer to signing statements when deciding what Congress intended in a piece of legislation--that doing so would violate the constitutional separation of powers. In contrast, Cross (1988) argues that courts will find (at times) that signing statements are useful as significant sources of material for statutory interpretation, just as are the views of agencies. For political science studies like Kelley and Marshall (2008), the president's motives include influencing judges and bureaucrats, along with voicing their concerns about the constitutionality of statutes.
This article starts with the idea that presidential signing statements are both directives and defenses--useful now or in the future for presidents, their staff and appointees, bureaucrats, and judges--that help determine how a statute is implemented and interpreted. My focus is on the detail and complexity of the directive the president constructs rather than on whether the president signs a statement for a given piece of legislation. Presidents decide the shape and content of the directive, just like they use rhetoric for pushing their current or future policy goals (e.g., Campbell and Jamieson 1990; Tulis 1987). …